Motor assembly for a powered surgical instrument

Abstract

A surgical instrument is provided for cutting bone and other tissue. The surgical instrument is powered by a pressurized fluid and includes a rotatable shaft connected to a dissection tool. The instrument includes a housing member comprising a one-piece base. A rotor housing chamber is defined by the base, and the rotatable shaft is located in the rotor housing chamber. A first hearing housing is defined by the base, located adjacent the rotor housing chamber, and houses a first bearing that engages the rotatable shaft. A second bearing housing is defined by the base, located on an opposite side of the rotor housing chamber from the first bearing housing, and houses a second bearing that engages the rotatable shaft. A passage is defined by the base and operable to direct a pressurized fluid through the base to the rotor housing chamber in order to rotate the rotatable shaft.

What is claimed is: 
     
       1. An assembly for a motorized surgical instrument, the assembly comprising:
 a one-piece base having an external base wall extending along a first longitudinal axis between a first base end and a second base end and defining:
 a pressurized fluid inlet; 
 a first bearing housing defined by a first internal wall of the base and located adjacent to the first base end, the first internal wall configured to contact a first bearing; 
 a second bearing housing defined by a second internal wall of the base and located adjacent to the second base end, the second internal wall configured to contact a second bearing; 
 a rotor housing chamber defined by the base between the first and second bearing housings, wherein the rotor housing chamber, the first bearing housing, the second bearing housing are one-piece with the one-piece base; 
 a passage defined by the base and configured to direct a pressurized fluid through the base to the rotor housing chamber; and 
 
 at least one bearing located in the first bearing housing or the second bearing housing and maintained in position by contact with the first internal wall or the second internal wall and configured to engage a rotatable shaft. 
 
     
     
       2. The assembly of  claim 1 , wherein the passage extends along a second longitudinal axis and the second longitudinal axis is offset from and substantially parallel to the first longitudinal axis and extends along the pressurized fluid inlet, the first bearing housing and a portion of the rotor housing chamber. 
     
     
       3. The assembly of  claim 1 , further comprising:
 a passage entrance defined by the base and located between the first bearing housing and the pressurized fluid inlet, whereby pressurized fluid entering the pressurized fluid inlet enters the passage through the passage entrance. 
 
     
     
       4. The assembly of  claim 3 , wherein the passage entrance is oriented at a nonzero angle relative to the passage. 
     
     
       5. The assembly of  claim 1 , further comprising:
 a motor housing having a motor housing wall defining an internal bore, wherein the one-piece base is formed as a unitary piece and is configured to be positioned within the internal bore of the motor housing. 
 
     
     
       6. The assembly of  claim 5 , further comprising:
 a hose assembly having a tube inlet and an exhaust outlet, wherein the tube inlet is configured to connect to the motor housing and direct a pressurized fluid to the passage. 
 
     
     
       7. The assembly of  claim 1 , further comprising:
 a rotor housing fluid entrance defined by the base, whereby pressurized fluid in the passage enters the rotor housing chamber through the rotor housing fluid entrance; and 
 a rotor housing fluid exit defined by the base, whereby fluid in the rotor housing chamber exits the rotor housing chamber through the rotor housing fluid exit. 
 
     
     
       8. The assembly of  claim 1 , further comprising:
 a transversely extending wall substantially perpendicular to the first longitudinal axis toward an interior of the one-piece base between the second bearing housing and the rotor housing chamber. 
 
     
     
       9. An assembly for a motorized surgical instrument, the assembly comprising:
 a one-piece base having an external base wall extending along a first longitudinal axis between a first base end and a second base end and defining:
 a pressurized fluid inlet; 
 a first bearing housing defined by a first internal wall of the base and located adjacent to the first base end; 
 a second bearing housing defined by a second internal wall of the base and located adjacent to the second base end; 
 a rotor housing chamber defined by the base between the first and second bearing housings, wherein the rotor housing chamber, the first bearing housing, the second bearing housing are one-piece with the one-piece base; 
 a passage defined by the base and configured to direct a pressurized fluid through the base to the rotor housing chamber; 
 
 a first bearing located in the first bearing housing and having a first external bearing surface contacting the first internal wall; 
 a second bearing located in the second bearing housing and having a second bearing surface contacting the second internal wall; and 
 a rotatable shaft located in the rotor housing chamber and engaging the first and second bearings. 
 
     
     
       10. The assembly of  claim 9 , wherein the one-piece base further comprises a bearing plate located in the second bearing housing and adjacent the second bearing. 
     
     
       11. The assembly of  claim 9 , further comprising:
 a fastener located at least partially in the first bearing housing and engaging the first bearing and the rotatable shaft. 
 
     
     
       12. The assembly of  claim 9 , further comprising:
 a bearing retainer member located at least partially in the first bearing housing and engaging the first bearing. 
 
     
     
       13. The assembly of  claim 9 , further comprising:
 a transversely extending wall substantially perpendicular to the first longitudinal axis toward an interior of the one-piece base between the second bearing housing and the rotor housing chamber. 
 
     
     
       14. The assembly of  claim 9 , further comprising:
 a passage entrance defined by the base and located between the first bearing housing and the pressurized fluid inlet, whereby pressurized fluid entering the pressurized fluid inlet enters the passage through the passage entrance. 
 
     
     
       15. The assembly of  claim 9 , wherein the one-piece base further comprises a rotor housing fluid entrance defined by the base, whereby pressurized fluid in the passage enters the rotor housing chamber through the rotor housing fluid entrance and engages the rotatable shaft; and
 wherein the one-piece base further comprises a rotor housing fluid exit defined by the base, whereby fluid in the rotor housing chamber exits the rotor housing chamber through the rotor housing fluid exit. 
 
     
     
       16. The assembly of  claim 9 , further comprising:
 a motor housing having a motor housing wall defining an internal bore, wherein the one-piece base is formed as a unitary piece and is configured to be positioned within the internal bore of the motor housing. 
 
     
     
       17. The assembly of  claim 9 , wherein the first bearing housing is open at the first base end and configured to receive the first bearing and the second bearing housing is open at the second base end and configured to receive the second bearing. 
     
     
       18. An assembly for a motorized surgical instrument, the assembly comprising:
 a one-piece base having an external base wall extending along a first longitudinal axis between a first base end and a second base end and defining:
 a pressurized fluid inlet adjacent to the first base end; 
 a first bearing housing defined by a first internal wall of the base and located adjacent to the pressurized fluid inlet, the first bearing housing configured to receive a first bearing at least through a first opening at the first base end, the first internal wall configured to contact the first bearing; 
 a second bearing housing defined by a second internal wall of the base and located adjacent to the second base end, the second bearing housing configured to receive a second bearing at least through a second opening at the second base end, the second internal wall configured to contact the second bearing; 
 a rotor housing chamber defined by the base between the first and second bearing housings, wherein the rotor housing chamber, the first bearing housing having the first internal wall, and the second bearing housing having the second internal wall are one-piece with the one-piece base; and 
 a passage defined by the base and extending along a second longitudinal axis, wherein the second longitudinal axis is offset from and substantially parallel to the first longitudinal axis and extends along the pressurized fluid inlet, the first bearing housing and a portion of the rotor housing chamber; 
 
 a passage entrance defined by the base and located between the first bearing housing and the pressurized fluid inlet, whereby pressurized fluid entering the pressurized fluid inlet enters the passage through the passage entrance; and 
 wherein the first bearing housing or the second bearing housing is configured for at least one bearing to be located in the first bearing housing or the second bearing housing to engage a rotatable shaft extending through the rotor housing chamber and into at least one of the first bearing housing or the second bearing housing. 
 
     
     
       19. The assembly of  claim 18 , wherein the passage entrance is oriented at a nonzero angle relative to the passage. 
     
     
       20. The assembly of  claim 18 , further comprising:
 a motor housing having a motor housing wall defining an internal bore, wherein the one-piece base is formed as a unitary piece and is configured to be positioned within the internal bore of the motor housing.